Insulating covering and method of making the same



G. B. BROWN Oct. 15, 1946.

INSULATING COVERING AND METHOD OF MAKING THE SAME Filed May 22, 1941 VINVENTOR koe Bean/A4 v aid-M.

Patented Oct. 15, 1946 INSULATING COVERING AND METHOD OF MAKING THE SAMEGeorge B. Brown, Martinsville, N. J., assignor to Johns-ManvilleCorporation, New York, N. Y., 7 -a corporation of New York ApplicationMay 22, 1941, Serial No. 394,592

16 Claims. (01. 154-28) The present invention relates tothermal-insulating products and the method of making the same, and moreparticularly, to insulating coverings of the type known as air-cellinsulation.

Heretofore, air-cell insulation, for example, pipe covering, has beenmanufactured from composited sheets of plane and corrugated paper.Conventionally, the .composite material in the form of a continuous webis drawn from a reel. adhesive is applied to the peaks of thecorrugations, and the material is then rolled upon a mandrel until wallsof the desired thickness are attained. The corrugations extend acrossthe paper, and hence, lengthwise of the completed covering. The tubesthus formed are divided into similar halves to permit their mountingupon a pipe, or the like, the two halves being connected by a covermember of plane asbestos or other paper, which serves as a hinge for thesegments and. which also conventionally includes an extending sealingflap.

The principal object of the instant invention is the provision of animproved thermal-insulating product generally of the type describedabove.

Another object of the invention is the provision of a tubular insulatingcovering in which the intermediate convolutions are composed entirely ofcorrugated paper, with the corrugations extending circumferentially ofthe plies in substantially non-nesting relationship with thecorrugations of adjacent plies.

A further object of the invention is the provision of a method ofmanufacture of an insulating material by a continuous process, includingthe steps of corrugating the paper and assembling it into article form.

My invention will be more fully understood and further objects andadvantages thereof will become apparent when reference is made to themore detailed description thereof which is to follow and to theaccompanying drawing, in which:

Fig. 1 is a perspective view of a tubular insulating covering inaccordance with the instant invention;

Fig. 2 is an enlarged sectional view taken on the line 2-2 of Fig. 1,looking in the direction indicated by the arrows;

Fig. 3 is a diagrammatic elevational view of an apparatus for carryingout the method of the instant invention;

Fig. 4 is an enlarged, fragmentary sectional view taken on the line 44of Fig. 3 and looking in the direction indicated by the arrows; and

Fig. 5 is a fragmentary plan view of corrugated 2 sheet material fromwhich the insulating covering is formed.

Referring now to the drawing, and particularly to Figs. 1 and 2, forpurposes of illustration there is shown a tubular insulating productgenerally of the type employed for the covering of pipes, and the like.It will be understood, however, that the instant invention may beemployed in insulating products of suitable form for covering variousother objects. The coveringof Figs.

1 and 2 comprises an inner-ply l2, preferably formed of a smooth orplane asbestos paper, or the like, a plurality of intermediate plies l4,having, in accordance with the invention, corrugations extendinggenerally circumferentially of the plies and in non-nesting relationshipwith corrugations of adjacent plies, and an outer covering sheet l5,preferably of plane paper. The inner and intermediate plies are severedon opposed radial lines, as indicated at H! and 20, to permit the tubeto be opened and applied about a pipe, or the like. The outer coveringsheet l6 extends, over the line of severance 18 to form a hinge, andincludes flap 22 which may be adhesively or otherwise secured across theother line of severance 29 to maintain the covering in assembledrelationship after installation. The several plies are secured togetherat their points of contactby a suitable adhesive, such as sodiumsilicate, casein adhesive, or other conventional material for thispurpose.

. Inner ply l2, intermediate plies ,l4, and outer ply H; are preferablyformed from a single sheet;

of material. That is, in the manufacture of the covering, each of theseveral plies constitutes a.

' the covering, but it is preferred that the paper be of relativelylight texture. corrugations 24 extend only generally circumferentiallyof the plies and are in the form of low-pitch spirals lengthwise of thetube. The corrugations of each ply are offset, at least for the mostpart, with of each ply are more or less of random width, for xample,they may be in repeating groups of, say, six or more corrugations ofdifferent widths (see Figs. 2 and 5). The several plies are maintainedin assembled relationship by a suitable adhesive, as previously referredto, at their points of contact.

Referring now to Figs. 3 and 4, in the manufacture of the insulatingcovering, the plane asbestos paper, or th like, is drawn from a suitablereel or other source of supply, as indicated at 30, and passes betweenimpressingrolls 32,34 provided with spirally extending projections orribs, as will be hereafter more fully described. After leaving theimpressing .rolls, .the paper passes over an adhesive applicator, suchas roller 36, rotating in contact with an adhesive supply 38. Th sheetis then rolled 'upon mandrel 40 to build up the necessary number ofplies or convolutions the corrugations of each ply being continuous withthe corrugations of adjacent plies. The tubular member thus formed isslit as indicated at 8 and 2D in Fig. 1. Rolls 32 and 34 are suitablymounted to permit their separation at any point in the operation. Forexample, roll 32 may be swingably mounted as indicated. Likewise, theadhesive applicator 36 may be swingably or otherwise movably mounted tobe removed from contact with the paper at certain intervals.

In the operation, rolls 32 and 34 are separated for a suitable timeinterval to permit the passage therebetween of suflicient paper to forman inner plane ply. They are then closed for a time interval to indentor corrugate a sufiicient length of paper to form the intermediateconvolutions or plies and are again separated to permit the passagetherebetween of sufficient paper for the outer plane ply l6, includingthe attaching flange 22. Adhesive applicator 3.6 is kept into contactwith the paper, except upon passage thereover of that required to formthe outermost ply. As will be readily understood, the operation ofmandrel 40 is timed with the movement of the rolls 3.2 and 34 and theapplicator 36 to and from operative position, either mechanically or byany suitable automatic means, to provide the previously describedarrangement of the several plies in the covering.

Impressing rolls 32 and 34 are provided with spiral ribs or projections(see Fig. 4), suitably pitched to form corrugations in the. paper sheetpassing .therebetween extending at a relatively small angle to thelongitudinal dimension of the sheet. Preferably, the ribs or projectionsare in groups of random width, such a group being indicated at ain Fig.4.

The rotative movements of rolls 32 and 3-; are synchronized to insurecooperation of the respective ribs and valleys in the impressing action.Alternatively, only one of the rolls 32 or 34 need be provided with thespiral ribs, and the other roll may be formed with a surface ofrelatively soft rubber, or the like, whereby the impressing action isproduced by but a single roll. In this case. exact synchronization ofrotation of the rollsis not of prime importance.

As will be understood by those skilled in the art, due to the generallylongitudinal but somewhat slanting corrugations, when the sheet isrolled on the mandrel, each convolution being slightly greater indiameter than the convolution therebelow, the corrugations will creeplongitudinally of the mandrel to a sufiicient extent to be out ofnesting relationship with the corru tions of the lower convolution. Onlyoccasionally will any nesting occur and this will be for such a shortinterval that the result will be a negligible nesting between theseveral convolutions. Furthermore, where the corrugations of differentwidths are employed, particularly such as described in sets of six ormore of random width, nesting is wholly avoided until the convolutionshave been displaced lengthwise to an extent corresponding to the numberof corrugations of the set. Hence, for practical purposes, there will beno nesting of successive convolutions.

Having thus described my invention in rather full detail, it will beunderstood by those skilled in the art that these details need not bestrictly adhered to, but that various changes and modifications willsuggest themselves, all falling within the scope of the invention asdefined by the subjoinedclaims.

What I claim is:

1. An insulating covering comprising a plurality of plies of corrugatedpaper, with each ply including corrugations of different widths, thecorrugations of each ply extending in substantially the same directionand oblique to the longitudinal dimension of the covering but inpredominantly non-nesting relationship with the corrugations of adjacentplies.

2. An insulating covering comprising a plurality of convoluted plies ofcorrugated asbestos paper, with the corrugations of each ply extendingin the same general direction and oblique to the longitudinal dimensionof the covering but continuous with and in predominantly non-nestingrelationship with the corrugations of adjacent plies.

3. A tubular insulating covering comprising a plurality of convolutedplies of asbestos paper, each ply including corrugations of difierentwidths and the corrugations of the several plies extending insubstantially the same direction and oblique to the longitudinaldimension of the covering but in predominantly non-nesting relationshipwith the corrugations of adjacent plies.

4. A tubular .insulating covering formed from a continuous strip,comprising a plurality of convoluted plies of asbestos paper includingan inner plane ply, a plurality of intermediate plies havingcorrugations extending generally circumferentially of each ply andoblique to the longitudinal dimension of the covering and which arecontinuous with but in predominantly non-nesting relationship with thecorrugations of adjacent plies, and an outer plane ply, and adhesivemeans securing the several plies together at their points of contact.

5. A tubular insulating covering formed from a continuous strip,comprising a plurality of convoluted plies of asbestos paper includingan inner plane ply, a plurality of intermediate plies havingcorrugations extending generally circumferentially of each ply andoblique to the 1ongitudinal dimension of the covering and which arecontinuous with but in predominantly non-nesting relationship with thecorrugations of adjacent plies, and an outer plane ply, and adhesivemeans securing the several plies together at their points of contact,the inner and intermediate plies being severed at opposite sides of thecenter of said covering, said outer ply extending across a line ofseverance to form a hinge.

6.. A tubular insulating covering formed from a continuous strip ofmaterial, comprising a plurality of convoluted plies of asbestosincluding an inner plane ply, a plurality of intermediate plies eachhaving corrugations of difi'erent widths, the corrugations of theseveral plies extending in substantially the same direction and obliqueto the longitudinal dimension of the covering and which are continuouswith but in predominantly non-nesting relationship with the corrugationsof adjacent plies, and an outer smooth ply, said inner and intermediateplies being severed on opposite sides of the center of said covering andsaid outer ply extending across one line of severance and including alapping flange adapted to extend across the other line of severance whenthe covering is applied, and adhesive means securing said several pliesin assembled relationship.

7. The method of making an insulating covering comprising impressing apaper sheet with a plurality of corrugations extending at an obliqueangle to the length thereof, and winding said sheet to form a pluralityof plies with the corrugations of each ply extending in the same generaldirection but offset with respect to the corrugations of adjacent plies.

8. The method of making an insulating covering comprising impressing aplane sheet of asbestos paper with a plurality of shallow corrugationsof difierent widths and extending obliquely to the longitudinaldimension of the sheet, and winding a plurality of plies from saidsheet, with the corrugations of each .ply extending in the same generaldirection but offset with respect to the corrugations of adjacent plies.

9. The method of making a tubular insulating covering comprisingimpressing an asbestos sheet with a plurality of shallow corrugationsextending generally lengthwise of the sheet but at an angle thereto, androlling said sheet into a tube of a plurality of integral convolutions,with said corrugations of each convolution extending circumferentiallyof the convolution and offset with respect to the corrugations ofadjacent convolutions.

10. The method of making a tubular insulating covering comprisingimpressing an asbestos sheet with a plurality of shallow corrugationsextending generally lengthwise of the sheet but at an angle thereto,applying an adhesive to the peaks-of said corrugations, and rolling aplurality of integral convolutions of said sheet on a mandrel extendingat right angles to the length thereof.

11. The method of making a tubular insulating covering comprisingrolling an asbestos sheet about a mandrel extending at approximatelyright angles to the length of said sheet while simultaneously impressinga length of said sheet'to form a plurality of convolutions with closelyspaced shallow corrugations extending generally lengthwise of the sheetbut at an angle thereto, and continuing said rolling operation to coversaid plurality of convolutions with an outer plane layer of saidasbestos sheet.

12. The method of making a tubular insulating covering comprisingrolling an asbestos sheet about a mandrel extending at approximatelyright angles to the length of said sheet while simultaneously impressinga length of said sheet 5 to form a plurality of convolutions withclosely spaced corrugations extending generally lengthwise of the sheetbut at an angle thereto, continuing said rolling operation to cover saidplurality of convolutions with an outer plane layer of said asbestossheet, and severing said intermediate convolutions on a line extendingthrough the center of said covering.

13. The method of making a tubular insulating covering comprisingdrawing a plane asbestos sheet through inoperative impressing means insuflicient amount to form an innner convolution about a mandrel,adjusting said means to impress a suiflcient length of said sheet toform a plurality of intermediate convolutions on said mandrel, withclosely spaced corrugations extending generally lengthwise or" the sheetand at an angle thereto, rendering said impressing means inoperative,and drawing a suflicient length of material through said means to forman outer plane convolution on said mandrel.

14. An insulating covering formed from a single continuous strip andcomprising a plurality of convoluted plies of asbestos paper includingan inner plane ply, a plurality of intermediate plies havingindentations arranged in predominantly non-nesting relationship andspacing each of said intermediate plies from an adjacent ply, and anouter plane ply, and adhesive securing the several plies together attheir points of contact.

15. A method of making a tubular covering from a continuous sheetcomprising winding a plane inner convolution from said sheet, indentinga length of said sheet to form protuberances of a character andarrangement to be in predominantly non-nesting relationship when saidlength is wound in a plurality of convolutions and winding a pluralityof convolutions thereof on said first convolution, and winding an outerplane convolution on said indented convolutions.

16. The method of making a tubular covering comprising drawing a planeasbestos sheet through inoperative impressing means in sufficient lengthto form an innner convolution about a mandrel, adjusting said means toim- 50 press a sufiicient length of said sheet to form a plurality ofintermediate convolutions on said mandrel, with closely spacedindentations of a character and arrangement to be in predominantlynon-nesting relationship in said interme- 55 diate convolutions,rendering said impressing means inoperative, and drawing a sufiicientlength of material through said means to form an outer plane convolutionon said mandrel, and winding said lengths upon said mandrel concurrently60 with said drawing action.

GEORGE B. BROWN.

